G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, n*k) * x^k ).

A206830

G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, n*k) * x^k ).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =34a(5) =520a(6) =14397a(7) =993806a(8) =222547738a(9) =98753510701

External references